The invention relates generally to medicine, and particularly to an administration strategy for delivering cytokines or cytokine antagonists at the intestinal mucosa. Preferably, the cytokines or cytokine antagonists are acid sensitive anti-inflammatory agents, such as IL10 and/or soluble TNF receptor. These antagonists may be delivered via an oral route. Preferably, inoculation occurs along with a suspension of recombinant Lactococcus lactis cells that are engineered to produce the respective proteins.
The mammalian immune system is diverse and complex, and includes natural and adaptive immune mechanisms and reactions. The immune system is often described in terms of either xe2x80x9chumoralxe2x80x9d or xe2x80x9ccellular immunexe2x80x9d responses. Humoral immunity refers broadly to antibody production and actions by B-cells, while cellular immunity is mediated by cells including T-cells, dendritic cells, neutrophils, monocytes and macrophages. T-cells and B-cells are two categories of lymphocytes.
One of the mechanisms by which the immune system normally acts and regulates itself includes the production of so-called xe2x80x9ccytokinesxe2x80x9d. Cytokines mediate several positive and negative immune responses. Cytokines normally act by binding to a receptor on a target cell. The activity of cytokines can be interfered with in several ways, for example by administration of soluble receptors (extracellular domains of the receptor) or by cytokine analogues or derivatives.
IL-10 is a cytokine capable of mediating a number of actions and/or effects. It is known that IL-10 is involved in controlling the immune responses of different classes or subsets of Th cells (T-helper cells).
Inflammatory bowel disease (xe2x80x9cIBDxe2x80x9d) refers to a group of gastrointestinal disorders characterized by a chronic nonspecific inflammation of portions of the gastrointestinal tract. Ulcerative colitis (xe2x80x9cUCxe2x80x9d) and Crohn""s Disease (xe2x80x9cCDxe2x80x9d) are the most prominent examples of IBD in humans. They are associated with many symptoms and complications, including growth retardation in children, rectal prolapse, blood in stools (e.g., melena and/or hematochezia), wasting, iron deficiency, and anemia, for example, iron deficiency anemia and anemia of chronic disease or of chronic inflammation. The etiology or etiologies of IBD are unclear. Reference hereto is made in Wyngaarden and Smith (eds.) Cecil""s Textbook of Medicine (W. B. Saunders Co. 1985), Berkow (ed.) The Merck Manual of Diagnosis and Therapy (Merck Sharp and Dohme Research Laboratories, 1982), and Harrison""s Principles of Internal Medicine, 12th Ed., McGraw-Hill, Inc. (1991).
The incidence of IBD varies greatly with geographic location. A collaborative study was commenced in Europe. It illustrated an incidence of 10.4 per 100,000 for UC and of 5.6 per 100,000 for CD, with 40% and 80% respectively higher incidences for UC and CD in northern centres when compared to those in the south. As both UC and CD are long time afflictions, they correspond-to real disturbances in the quality of life. Crohn""s disease has a bimodal age distribution of onset, showing striking peaks in incidence at 20 and at 50 years of age. A higher incidence and more grievous disease profile is associated with those that peak at a younger-age. This makes CD especially poignant as afflicted adolescents and young adults are virtually deprived of the high expectations of life particularly associated with this age group.
Ulcerative colitis refers to a chronic, nonspecific, inflammatory, and ulcerative disease having manifestations primarily in the colonic mucosa. It is frequently characterized by bloody diarrhea, abdominal cramps, blood and mucus in the stools, malaise, fever, anemia, anorexia, weight loss, leukocytosis, hypoalbuminemia, and an elevated erythrocyte sedimentation rate (xe2x80x9cESRxe2x80x9d). Complications can include hemorrhage, toxic colitis, toxic megacolon, occasional rectovaginal fistulas, and an increased risk for the development of colon cancer.
Ulcerative colitis is also associated with noncolon complications, such as arthritis, ankylosing spondylitis, sacroileitis, posterior uveitis, erythema nodosum, pyoderma gangrenosum, and episcleritis. Treatment varies considerably with the severity and duration of the disease. For instance, fluid therapy to prevent dehydration and electrolyte imbalance is frequently indicated in a severe attack. Additionally, special dietary measures are sometimes useful. Medications include various corticosteroids, sulphasalazine and some of its derivatives, and possibly immunosuppressive drugs.
Crohn""s Disease shares many features in common with ulcerative colitis. Crohn""s Disease is distinguishable in that lesions tend to be sharplydemarcated from adjacent normal bowel, in contrast to the lesions of ulcerative colitis which are fairly diffuse. Crohn""s Disease predominately afflicts the ileum (ileitis) and the ileum and colon (ileocolitis). In some cases, the colon alone is diseased (granulomatous colitis) and sometimes the entire small bowel is involved (jejunoileitis). In rare cases, the stomach, duodenum, or esophagus are involved. Lesions include a sarcoid-type epithelioid granuloma in roughly half of the clinical cases. Lesions of Crohn""s Disease can be transmural including deep ulceration, edema, and fibrosis, which can lead to obstruction and fistula formation as well as abscess formation. This contrasts with ulcerative colitis which usually yields much shallower lesions, although occasionally the complications of fibrosis, obstruction, fistula formation, and abscesses are seen in ulcerative colitis as well.
Treatment is similar for both diseases and includes steroids, sulphasalazine and its derivatives, and immunosuppressive drugs such as cyclosporin A, mercaptopurine and azathioprine. More recently developed treatments, some still in clinical trials, involve systemic administration (by injection) of TNF blocking compounds such as TNF-antibodies or soluble TNF receptor.
IBD represents a genuine problem in public health because of the absence of etiologic treatment. Although many patients are managed successfully with conventional medical therapy, such as anti-inflammatory corticosteroid treatment, most will have recurrent activity of disease, and two-thirds will require surgery.
The cause of inflammatory bowel diseases is unknown. The pathogenesis of CD and UC probably involves interaction between genetic and environmental factors, such as bacterial agents, although no definite etiological agent has been identified so far. The main theory is that abnormal immune response, possibly driven by intestinal microflora, occurs in IBD. It is well established that T-cells play an important role in the pathogenesis. Activated T-cells can produce both anti-inflammatory and pro-inflammatory cytokines. With this knowledge in hand, IBD can be counteracted in a rational manner. Novel anti-inflammatory therapies, which make use of neutralizing monoclonal antibodies or anti-inflammatory cytokines, show the possibility to modulate the immune disregulations causative to IBD. A highly prominent and effective new therapy is systemic treatment with anti-TNF monoclonal antibodies as mentioned above. Single intravenous doses, ranging from 5 to 20 mg/kg, of the cA2 infliximab antibody resulted in a drastic clinical improvement in active Crohn""s disease. The use of systemically administered recombinant IL-10 in a 7 day by day treatment regime using doses ranging from 0.5 to 25 xcexcg/kg showed reduced Crohn""s disease activity scores and increased remission. A number of very promising therapies, either tangling pro-inflammatory cytokines or the establishment of T-cell infiltrates, are currently emerging from experimental models. All these strategies however require systemic administration. The severe complications of IBD can be seriously debilitating, and eventually may lead to death.
In U.S. Pat. No. 5,368,854, assigned to Schering Corp., a method is disclosed for using IL-10 to treat inflammatory bowel diseases in mammals. In this method, the cytokine is administered to a mammal having IBD. The administration of IL-10 as described in this reference is parenteral, such as intravascular, preferably intravenous. Such a route of administration for a (human) patient suffering from IBD is, however, not without drawbacks. A much easier and more convenient way would be oral administration of a medicament comprising a cytokine such as IL-10 or a cytokine-antagonist which has a similar therapeutic activity. More importantly, localized release of the therapeutic agent allows for higher efficacy and less unwanted side effects due to systemic activities.
In WO 97/14806, assigned to Cambridge University Technical Services Ltd., a method is disclosed for delivering biologically active polypeptides and/or antigens by using non-invasive bacteria, such as Lactococcus, by intranasally administering the polypeptides to the body, especially at the mucosa.
However, treating an inflammatory bowel disease such as chronic colitis or Crohn""s disease with an acid sensitive cytokine like IL-10, is a very delicate and difficult task to accomplish. Therefore, a system needs to be developed wherein the active compound (e.g., a cytokine or a soluble receptor) is delivered directly at the place where the compound is expected to exert its activity taking into account the acid sensitivity of many cytokines, particularly IL-10, since, after oral administration, the delivery vehicle needs to pass through the acidic environment of the stomach. Furthermore, various digestive enzymes degrade polypeptides as they pass through the stomach and the gut. Last, but not least, in situ administration of the agent may allow one to reach therapeutically effective concentrations difficult to achieve by most systemic routes of administration due to systemic toxicity or other limitations.
The invention generally relates to an administration strategy for delivering cytokines, preferably of acid sensitive anti-inflammatory agents, such as IL10 and/or a soluble TNF receptor, via the oral route to the intestinal mucosa. The invention preferably involves inoculation along with a suspension of live recombinant Lactococcus lactis cells engineered to produce the respective proteins. For example, mice having a chronic inflammation of the distal colon induced by administration with dextran sulfate sodium (DSS). The treatment, as scored by histological evaluation, clearly showed a regression of the inflammation and disease symptoms. The finding is highly unexpected since, in order to exert activity at the colon following oral administration, the delivery system had to pass the acidic environment of the stomach and the upper part of the small intestine.